Elastic composite material, preparation method thereof and trousers product

Abstract

The invention provides an elastic composite material and a preparation method thereof and a pants product, the elastic composite material comprises a first non-woven fabric, a second non-woven fabric and an adhesive elastic band arranged between the first non-woven fabric and the second non-woven fabric, the adhesive elastic band is an SEBS copolymer or contains an SEBS copolymer, and the adhesive elastic band is made of a thermoplastic elastomer. Wherein the adhesive elastic band imparts elasticity to the elastic composite material. The hot melt adhesive property and elasticity of the SEBS copolymer are combined, the inner layer non-woven fabric and the outer layer non-woven fabric of the waistline assembly are bonded together through online melting of the SEBS copolymer, stretchability and viscidity are provided at the same time, existing waistline rubber band and glue bonding is replaced, only the waistline non-woven fabric and the SEBS material are used for compounding, and in addition, the waistline elastic partition design is adopted, so that the elasticity of the waistline assembly is greatly improved. And the advantages of cost saving, air permeability, softness, wearing comfort improvement and the like are brought.

Description

Technical Field

[0001] The invention relates to an elastic composite material and a preparation method thereof and application in trousers products. Background Art

[0002] With the advancement of technology and the increasing diversity of consumer demand, stretchable nonwoven composites, as a new type of material that combines flexibility, breathability and adaptability, have shown great potential in the field of textiles and personal hygiene products. Such composite materials usually consist of a multi-layer structure, with a nonwoven fabric substrate as the core, and an elastic layer embedded on or inside it. The elastic layer can be a structure woven from elastic films, elastic strands (such as rubber bands, spandex yarns, etc.) or special elastic fibers, designed to provide elastic recovery and fit to the final product.

[0003] In the field of pants products, especially for the market segments such as Adult Care Pants (AC Pants), Female Care Pants (FC Pants), and Baby Child Care Pants (BCC Pants), the design of the elastic waist is directly related to the comfort, sealing and use effect of the product. Traditionally, the elastic waist of these products generally adopts elastic strands embedded between the material layers and fixed by adhesives to achieve the required elasticity. Although this method can effectively provide the required stretch performance, during long-term wear, due to the direct compression of the elastic strands on the skin, it often causes obvious marks on the waist area of ​​the user, which not only reduces the comfort of wearing, but also may cause discomfort to the skin, affecting the overall user experience of consumers.

[0004] Specifically, existing waist designs are mainly divided into the following types:

[0005] 1. Elastic and adhesive composite technology: ordinary elastic or fine-denier elastic is wrapped in adhesive (hot melt adhesive), and then laminated with waist non-woven fabric;

[0006] 2. Glue-free waist fixing technology: Using ultrasonic and other point pressure processes, the elastic band is directly fixed (welded) on the waist material, which not only retains the elasticity but also avoids the use of adhesives;

[0007] 3. Elastic film and non-woven fabric composite technology: The elastic film is laminated with the waist non-woven fabric, and then perforated to increase breathability;

[0008] 4. Elastic non-woven fabric integrated design: elastic non-woven fabric is directly used as the waist material, getting rid of the dependence on elastic bands and adhesives.

[0009] Although waist design technology continues to advance, it still faces many challenges. Specifically, as a core material, the elastic properties of rubber are greatly restricted by the raw material supplier, and the tension and elasticity values ​​are difficult to adjust at will, which limits the flexibility of design to a certain extent. When trying to improve the wearing experience by replacing it with fine-denier rubber, although better comfort can be achieved, the increase in the number of rubber roots inevitably pushes up production costs, bringing additional economic pressure to manufacturers.

[0010] Traditionally, the combination of elastic and adhesive is a common choice for waist design, but this design often makes the product feel hard and lacks softness. At the same time, the use of adhesives not only increases the cost of raw materials and the complexity of the production process, but may also cause safety and odor problems during product use, and raise environmental concerns.

[0011] In contrast, material innovations using elastic films or elastic nonwovens have improved the softness of the product to a certain extent. However, these materials also have significant defects: the elasticity is often too strong and needs to be regulated through complex cutting or punching processes to ensure the fit of the garment. In addition, the performance of elastic films and elastic nonwovens in terms of breathability is still unsatisfactory, making it difficult to meet consumers' higher pursuit of comfort.

[0012] For the high-end market, Lycra elastic is highly favored due to its excellent performance. However, the use of Lycra elastic is also accompanied by many challenges. Its specific decitex, tension and thickness requirements must rely on adhesives and non-woven fabrics for lamination, which not only increases the difficulty of production, but may also lead to an increase in product costs. More importantly, the bright colors of Lycra elastic (in addition to white, there are blue, pink or other specific colors) can easily form a visual focus on the product. Once damaged during the process, it will seriously affect the overall appearance and craftsmanship of the product. In addition, the uneven tension of Lycra elastic may also cause the appearance of the waistline to be uneven, which in turn affects the folding and storage effect of the pants, causing inconvenience to consumers.

[0013] On this basis, the innovation trend in the industry is moving towards reducing or even completely eliminating the use of adhesives to address the limitations of traditional methods. Patented technologies such as WO9734506A1 and CN110290771A are two examples of this trend. They cleverly adopt an innovative fixing mechanism - by setting independent bonding parts on both sides of the elastic strands, and arranging these bonding parts across them at a spacing less than the diameter of the elastic strands, the elastic strands are firmly fixed in the material layer. This adhesive-free elasticized material has a cost advantage because no adhesive is required to fix the elastic strands in the material. Therefore, in addition to providing appearance, comfort and fit benefits, the development of other elastic composite materials that do not include adhesives can also help reduce the overall cost of trouser products.

[0014] In summary, the development of elastic composite materials that do not rely on adhesives not only represents technological progress and innovation, but also brings the dual benefits of reducing total costs and improving product quality to the textile industry such as trousers. The continued development of this trend is expected to lead waistline design and even the entire textile industry to a new stage of being more environmentally friendly, efficient and comfortable. Summary of the invention

[0015] Therefore, the purpose of the present invention is to provide a new elastic composite material and a preparation method thereof which does not use any adhesive at all, in view of a series of problems caused by the use of adhesives in traditional elastic composite materials.

[0016] Styrene-ethylene-butylene-styrene, or SEBS for short, is an important thermoplastic elastomer (TPE) that has properties similar to rubber and does not require vulcanization. SEBS threads can be used in the form of monofilament threads or melted in a melt pool and passed through a spinneret (extruded) to form an elastic film material that acts as an elastic band (rubber). SEBS material begins to melt (without breaking) at a temperature of about 80°C and, when melted, has properties similar to hot melt adhesives that can bond materials together.

[0017] The chemical structure of SEBS is as follows:

[0018]

[0019] The weight percentages of the repeating units of SEBS used in the present invention are: polystyrene 13-58 wt %; polyethylene butylene 42-87 wt %, and its melt flow rate is 1-18 g / 10min (measured according to GB / T 3682-2000).

[0020] Based on the in-depth study of the properties of SEBS, the inventors of the present invention creatively use SEBS materials to manufacture waist elastic composite materials, melt the SEBS materials online to make them sticky, then apply SEBS as an adhesive on the non-woven fabric, and bond the inner layer and outer layer of the waist non-woven fabric together, so that the SEBS material can simultaneously provide stretchability and stickiness for the waist elastic composite material. The waist elastic material thus prepared can be used to replace the current waist rubber band and adhesive bonding in the application of trouser waist, and only the waist non-woven fabric and SEBS material are used for compounding. This technology will bring advantages in terms of cost, breathability, softness, etc.

[0021] Based on the characteristics of SEBS, the formula of SEBS can be adjusted according to the tension required for the waist circumference, including tension, elasticity and viscosity to achieve a customized effect, and is no longer limited by the tension and elasticity requirements of the raw materials.

[0022] In the present invention, MD direction (machine direction, longitudinal direction) refers to the direction of machine running and output, and CD direction (material width direction, cross direction) refers to the direction perpendicular to the machine running direction.

[0023] A first aspect of the present invention provides an elastic composite material, the elastic composite material comprising:

[0024] First nonwoven fabric;

[0025] The second nonwoven fabric, and

[0026] A plurality of adhesive elastic bands are disposed between the first nonwoven fabric and the second nonwoven fabric, wherein the adhesive elastic bands are SEBS copolymers or contain SEBS copolymers,

[0027] The first nonwoven fabric and the second nonwoven fabric are bonded by the plurality of adhesive elastic bands to form the elastic composite material, and the adhesive elastic bands impart elasticity to the elastic composite material.

[0028] In some embodiments of the present invention, the elastic composite material has longitudinal and transverse dimensions, and the adhesive elastic belt comprises a plurality of adhesive elastic belts oriented in the longitudinal direction, and the plurality of adhesive elastic belts oriented in the longitudinal direction are spaced apart from each other in the transverse direction; and / or the adhesive elastic belt comprises a plurality of adhesive elastic belts oriented in the transverse direction, and the plurality of adhesive elastic belts oriented in the transverse direction are spaced apart from each other in the longitudinal direction.

[0029] In some embodiments of the present invention, the adhesive elastic tape has an aspect ratio of 2 to 100, preferably an aspect ratio of 16 to 84. In a preferred embodiment of the present invention, the adhesive elastic tape has a width of 5 to 50 μm, preferably 10 to 30 μm.

[0030] In a preferred embodiment of the present invention, the adhesive elastic belt consists entirely of SEBS copolymer.

[0031] According to the elastic composite material provided by the present invention, the SEBS copolymer generally has a molecular weight of 0.88-0.96 g / cm 3 and in some embodiments about 0.96 g / cm 3 density.

[0032] According to the elastic composite material provided by the present invention, the plurality of adhesive elastic bands generally have a thickness of 60 g / m 2 or less and in some embodiments 48 to 50 g / m 2 The total basis weight.

[0033] According to the elastic composite material provided by the present invention, the weight average molecular weight (M w ) is 100,000-200,000 g / mol, preferably 130,000-150,000 g / mol.

[0034] The inventors of the present invention have found through a large number of experimental tests that when the adhesive elastic band contains a mixture of SEBS with a weight average molecular weight of 140,000-145,000 and SEBS with a weight average molecular weight of 130,000-135,000 in a weight ratio of 3.5-5.5:1, an elastic composite material with the best comprehensive performance can be obtained with the least amount of SEBS.

[0035] Preferably, the content of styrene monomer in the SEBS copolymer may be 13-58 wt %, more preferably 18-31 wt %.

[0036] Preferably, the SEBS copolymer has a melt flow rate (MFR) of 1 to 18 g / 10 min, preferably 7 to 18 g / 10 min, measured at 230° C. and a load of 2.16 kg.

[0037] The inventors of the present invention have found through a large number of experimental studies that, compared with elastic composite materials in the form of films, those in the form of threads can better reduce costs, improve product air permeability and softness, and simplify the process.

[0038] A second aspect of the present invention provides a method for preparing an elastic composite material, the method comprising:

[0039] stretching a plurality of bonded elastic filaments in a machine direction;

[0040] placing the adhesive elastic yarn between the first nonwoven fabric and the second nonwoven fabric along the machine direction in a stretched state;

[0041] The first nonwoven fabric and the second nonwoven fabric are bonded by the plurality of bonding elastic threads by means of heat bonding, pressure bonding or ultrasonic bonding, and a plurality of bonding elastic bands are formed between the first nonwoven fabric and the second nonwoven fabric, and the elastic composite material is obtained after relaxation,

[0042] The adhesive elastic filaments comprise SEBS copolymers, and the adhesive elastic filaments impart elasticity to the elastic composite material.

[0043] According to the preparation method provided by the present invention, the bonding temperature can be 130-190° C., preferably 170-190° C. During the bonding process, the SEBS copolymer can be adjusted to a desired viscosity by controlling the heating temperature.

[0044] The third aspect of the present invention provides a method for preparing an elastic composite material, comprising heating an adhesive elastic material containing a SEBS copolymer to 130-190°C to melt it, using a spinneret assembly to make the molten adhesive elastic material into an adhesive elastic thread, placing the adhesive elastic thread between a first non-woven fabric and a second non-woven fabric in a stretched state, bonding the first layer of non-woven fabric and the second non-woven fabric by thermal bonding, pressure bonding, self-bonding of the material itself, and / or ultrasonic bonding, and forming a plurality of adhesive elastic bands between the first non-woven fabric and the second non-woven fabric.

[0045] The adhesive elastic band is SEBS or styrene-butadiene-styrene (SBC) copolymer or contains SEBS copolymer, and the adhesive elastic band between the first and second non-woven fabrics can be plain or form a specific pattern, including but not limited to corrugations, S curves, channels, etc.

[0046] In some embodiments of the present invention, the first nonwoven fabric and / or the second nonwoven fabric is preferably an elastic nonwoven fabric, and the preparation method may further include: stretching the elastic composite material along a machine direction to adjust the tension of the elastic composite material.

[0047] In some embodiments of the present invention, the preparation method may further include the following steps of preparing the bonded elastic thread:

[0048] heating an adhesive elastic material comprising a SEBS copolymer until it melts;

[0049] The melted adhesive elastic material is formed into adhesive elastic yarns by using a spinneret assembly.

[0050] In a preferred embodiment of the present invention, the diameter of the adhesive elastic thread is 2-20 μm, more preferably 5-16 μm.

[0051] In a preferred embodiment of the present invention, the first nonwoven fabric and the second nonwoven fabric are bonded by placing a laminate of the first nonwoven fabric and the second nonwoven fabric with a plurality of adhesive elastic threads placed therebetween on or passing through a normal (flat) roller or a patterned roller to form a pattern (such as corrugations, S curves, channels, etc.).

[0052] Without departing from the spirit and scope of the present invention, the preparation method of the present invention may also include performing various additional processing and / or finishing steps known in the art, such as cutting, stretching, etc. It should be noted that due to its inherent extensibility, the composite material of the present invention may not be subject to any additional conventional post-forming operations. However, such processes may be employed when necessary. For example, the composite material may optionally be mechanically stretched in the transverse and / or longitudinal directions to enhance extensibility.

[0053] The elastic composite material of the present invention can be used in a wide variety of applications. As mentioned above, the elastic composite material can be used in absorbent articles. "Absorbent article" generally refers to any article that can absorb urine, blood, water or other fluids. Some examples of absorbent articles include, but are not limited to, personal care absorbent articles, such as diapers, training pants, absorbent underpants, incontinence products, feminine hygiene products (e.g., sanitary napkins, pantiliners, etc.), swimsuits, etc.; medical absorbent articles, such as clothing, fenestration materials, pads, mattresses, bandages, absorbent sheets and medical wipes; food service tissues; clothing products, etc. Typically, absorbent articles include a substantially liquid-impermeable layer (e.g., an outer cover), a liquid-permeable layer (e.g., a body-side liner, a surge layer, etc.) and an absorbent core. In a particular embodiment, the elastic composite material of the present invention can be used to provide a waist circumference of a pant product.

[0054] A fourth aspect of the present invention provides a pant product having a front region, a back region and a crotch region extending between and connecting the front region and the back region, the absorbent article comprising:

[0055] an absorbent assembly extending longitudinally between the front region and the back region and comprising an inner layer facing the wearer, an outer layer facing away from the wearer, and an absorbent structure disposed between the inner layer and the outer layer; and

[0056] a waist component attached to the absorbent component and defining a waist opening of the absorbent article,

[0057] The waist component comprises the elastic composite material provided by the present invention, or is formed by the elastic composite material provided by the present invention.

[0058] According to the trousers product provided by the present invention, preferably, the elastic partitions of the waist component are as follows:

[0059] The front waist of the trousers product is divided into four elastic regions from top to bottom along the longitudinal direction, and the width ratio and stretch ratio of each elastic region are as follows: the width ratio of the first region is 5%-8%, and the stretch ratio is 270%-310%; the width ratio of the second region is 10%-20%, and the stretch ratio is 220%-270%; the width ratio of the third region is 5-15%, and the stretch ratio is 180%-250%; the fourth region includes but is not limited to an inelastic region or a region with lower elasticity than the third region;

[0060] The rear waistline of the pants product is divided into four elastic zones from top to bottom along the longitudinal direction, and the width ratio and stretch ratio of each elastic zone are as follows: the width ratio of the first zone is 5%-8%, and the stretch ratio is 270%-310%; the width ratio of the second zone is 10%-20%, and the stretch ratio is 220%-270%; the width ratio of the third zone is 15%-35%, and the stretch ratio is 180%-250%; the fourth zone includes but is not limited to an inelastic zone or an elasticity lower than that of the third zone.

[0061] The schematic diagram of the elastic partition of the waist component is as follows Figure 3 and Figure 4 As shown. Among them, Figure 3 It is a schematic diagram of elastic partitions of the waist assembly of the trousers product provided by the present invention; Figure 4 It is a schematic diagram of the distribution of the elastic partitions of the waist assembly of the trousers product provided by the present invention in the trousers product.

[0062] The fifth aspect of the present invention provides the use of the elastic composite material in absorbent products, such as diapers, training pants, absorbent underwear, night pants, and daily pants. The elastic composite material of the present invention is used in absorbent products to provide better air permeability, softness and cost-effectiveness, and the design of zoned elasticity also better meets the requirements of each area, thereby providing a more comfortable use experience.

[0063] The present invention combines the hot melt adhesive properties and elasticity of SEBS copolymers, and bonds the inner and outer non-woven fabrics of the waist assembly together by melting the SEBS copolymer online, while providing stretchability and viscosity, replacing the current waist rubber bands and adhesive bonding, and only using the waist non-woven fabric and SEBS materials for compounding, thereby bringing benefits in terms of cost savings, breathability, softness, etc. Compared with the prior art, the elastic composite material of the present invention has a lower gram weight while maintaining similar elasticity and strength properties, thereby reducing raw material costs and carbon emissions, and being more environmentally friendly and green. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The embodiments of the present invention are described in detail below with reference to the accompanying drawings, wherein:

[0065] Figure 1is a photograph of the elastic composite material prepared in Example 1;

[0066] Figure 2 is a photograph of the trousers product prepared in Example 2;

[0067] Figure 3 It is a schematic diagram of elastic partitions of the waist assembly of the trousers product provided by the present invention;

[0068] Figure 4 It is a schematic diagram of the distribution of the elastic partitions of the waist assembly of the trousers product provided by the present invention in the trousers product. DETAILED DESCRIPTION

[0069] The present invention is further described in detail below in conjunction with specific embodiments. The given examples are only for illustrating the present invention, but not for limiting the scope of the present invention.

[0070] The SEBS copolymer used in the embodiment is purchased from Yisibang New Materials (Shanghai) Co., Ltd., including G1645 model (molecular weight of 142000) and G1657 model (molecular weight of 133000), which can be mixed in a weight ratio of 3.5~5.5: 1; the content of styrene monomer is 13-58 wt%, and the melt flow rate (MFR) of the SEBS copolymer measured at 230°C and 2.16 kg load is 3~6 g / 10min. The non-woven fabric used in the embodiment is a spunbond non-woven fabric purchased from Berry Non-woven Fabrics (China) Co., Ltd.

[0071] Example 1

[0072] The SEBS copolymers of model G1645 and G1657 were mixed in a ratio of 4.5:1 by twin-screw heating to prepare an adhesive elastic material with a density of 0.96 g / cm 3 .

[0073] The prepared adhesive elastic material is heated to 180°C to melt, and the molten adhesive elastic material is passed through a spinneret assembly to form an adhesive elastic filament; after cooling, the adhesive elastic filament is stretched; the adhesive elastic filament is cooled and gradually solidified to form an adhesive elastic strip of 0.083 g / strand / m, and the elastic strip is stretched in a machine direction to obtain a tension suitable for the product.

[0074] Under the stretched state of the adhesive elastic strip, multiple adhesive elastic strips are compounded between the first nonwoven fabric and the second nonwoven fabric in the machine direction, compacted and then relaxed to make the basis weight of the multiple adhesive elastic bands formed be 27.64 gsm, that is, the elastic composite material of the present invention is obtained, with a basis weight of about 32 gsm.

[0075] The photo of the elastic composite material prepared in this embodiment is shown in FIG. Figure 1 shown.

[0076] Example 2

[0077] The SEBS copolymers of model G1645 and G1657 were mixed in a ratio of 4.5:1 by heating through a twin-screw extruder to prepare an adhesive elastic material.

[0078] The prepared adhesive elastic material is heated to 160°C to melt, and the molten adhesive elastic material is passed through a spinneret assembly to form adhesive elastic threads; the adhesive elastic threads are then stretched after cooling; the adhesive elastic threads are cooled and gradually solidified to form adhesive elastic strips of 0.07 g / thread / m, and the elastic strips are stretched in a machine direction to obtain the tension required for a suitable product.

[0079] Under the stretched state of the adhesive elastic strip, multiple adhesive elastic strips are compounded between the first non-woven fabric and the second non-woven fabric in the machine direction, compacted and then relaxed to make the basis weight of the multiple adhesive elastic bands formed be 25gsm, that is, the elastic composite material of the present invention is obtained, with a basis weight of about 30gsm.

[0080] Example 3

[0081] The SEBS copolymers of model G1645 and G1657 were mixed in a ratio of 5.5:1 by heating through a twin-screw extruder to prepare an adhesive elastic material.

[0082] The prepared adhesive elastic material is heated to 170°C to melt, and the molten adhesive elastic material is passed through a spinneret assembly to form adhesive elastic threads; the adhesive elastic threads are then stretched after cooling; the adhesive elastic threads are cooled and gradually solidified to form adhesive elastic strips of 0.09 g / thread / m, and the elastic strips are stretched in the machine direction to obtain the tension required for a suitable product.

[0083] Under the stretched state of the adhesive elastic strip, multiple adhesive elastic strips are compounded between the first non-woven fabric and the second non-woven fabric in the machine direction, compacted and then relaxed to make the basis weight of the multiple adhesive elastic bands formed be 30gsm, that is, the elastic composite material of the present invention is obtained, with a basis weight of about 40gsm.

[0084] Comparative Example 1

[0085] The SEBS copolymers of model G1645 and G1657 were mixed in a ratio of 4.5:1 by a twin-screw heating to prepare an adhesive elastic material, and heated to 180°C to melt.

[0086] The melted adhesive elastic material is rotated by a rotating roller combined with a glue machine to form a flat elastic film, and then stretched by a traction roller in front to form a fish-scale elastic film with holes; it continues to cool and gradually solidifies to form a 30gsm fish-scale breathable adhesive elastic film.

[0087] When the fish-scale breathable adhesive elastic film is stretched, the adhesive elastic film is laminated between the first nonwoven fabric and the second nonwoven fabric in the machine direction. After stretching and laminating and compacting, the elastic composite material of the present invention is obtained, with a basis weight of about 35 gsm.

[0088] Example 5

[0089] Based on the elastic composite material prepared in Example 1, the overall trousers product can be prepared according to the following process:

[0090] After passing through the material unwinding station, Example 1 passes through the slitting station and is cut into two parts, the front and rear waistline, and then enters the main machine. At the compounding station, it is compounded with the front and rear ends of the absorbent core according to the position requirements, and finally cut into independent products by a cutter.

[0091] The photos of the trousers product prepared in this embodiment are as follows Figure 2 shown.

[0092] Performance Testing

[0093] Hereinafter, the elastic composite materials prepared in Examples 1-3 were subjected to performance tests and compared with Kimberly-Clark elastic film (C2011-0951) and ordinary rubber bands (Lycra rubber bands).

[0094] For Lycra rubber bands, the method for making an elastic composite material is as follows: after the Lycra rubber bands are unwound, they are pulled to a specified position through a guide wheel, rubber band glue is applied with a glue gun, and then pulled through a guide wheel, and bonded to the upper and lower waist non-woven fabrics in the main machine to form an overall elastic composite material.

[0095] For Kimberly-Clark elastic film (C2011-0951), the method for making the elastic composite material is as follows: after the elastic film is unrolled, it is stretched to a specified position by traction in a main machine, and rubber band glue is sprayed with a glue gun, and then it is bonded to the upper and lower waist non-woven fabrics by traction to form an overall elastic composite material.

[0096] Comparing the elastic yarn of Example 1 with the fish-scale-shaped breathable elastic film of Example 5, the advantages of the elastic yarn are mainly reflected in:

[0097] 1. With similar elasticity and strength properties, elastic yarn has a smaller weight (27.64g vs 30g), thus achieving a lower raw material price.

[0098] 2. Even the fish-scale-like breathable elastic membrane is still far less breathable than the elastic threads arranged in thread-like form. In terms of specific values, it is about 2 / 3 of that.

[0099] 3. From a technological perspective, the overall process of preparing elastic silk is simpler and smoother, so the actual operation efficiency is higher and the production cost is lower.

[0100] (one) Tensile strength and elongation test

[0101] 1. Test purpose: To measure the tensile strength and elongation of elastic materials when stretched.

[0102] 2. The instrument is MTS Criterion TM -Model 43; test method is KCC STM 5667

[0103] 3. Preparation before the test:

[0104] (1) Determine the appropriate load cell for the tensile tester and install the appropriate fixture, ensuring that there is no accumulation of impurities on the fixture and the clamping surface and that there are no indentations or other damage on the fixture surface.

[0105] (2) The air pressure for operating the clamps is set to 60 psi; the clamp spacing is 101.6 ± 1 mm (4 ± 0.04 inch); and the linkage speed is 305 ± 10 mm / min (12 ± 0.4 inch).

[0106] (3) Sample preparation: Cut a specimen with a width of 25.4±3 mm (1±0.125 inch) and a length of 165.1±3 mm (6.5±0.125 inch) (this is the minimum length to ensure that both ends of the material can be fully clamped by the upper and lower clamps).

[0107] 4. Test method:

[0108] Place the specimen symmetrically in the fixture, with the longer dimension parallel to the direction of load application. Close the clamp and start the tensile tester. When the return limit is reached, the fixture will return. Record the tensile strength and elongation. Report the peak load with an accuracy of 0.01gf and the elongation with an accuracy of 0.1%. The test results are shown in Table 1.

[0109] Table 1

[0110]

[0111] (II) Peel strength test

[0112] 1. Test purpose: To measure the peel strength of elastic materials after compounding.

[0113] 2. Instrument: MTS Criterion TM -Model 43

[0114] 3. Preparation before the test:

[0115] Determine the appropriate load cell for the tensile tester, install the appropriate fixture, and ensure that there is no accumulation of foreign matter on the fixture and the clamp surface and no indentation or other damage on the clamp surface. Set the air pressure of the operating fixture to 60psi. Select the test method as KCC STM5668, adjust the fixture spacing to 50.8±1mm (2±0.04inch), and the connecting rod speed to 305±10 mm / min (12±0.4inch).

[0116] Sample preparation:

[0117] Cut a specimen with a width of 50.8±3mm (2±0.125inch) and a length of 50.8±3mm (2±0.125inch) (this is the minimum length to ensure that both ends of the material can be fully clamped by the upper and lower clamps).

[0118] 4. Test method:

[0119] Place the specimen symmetrically in the fixture with the longer dimension parallel to the direction of load application. Close the clamp. Start the tensile tester. Set the fixture to stop and return after 150 mm displacement. Record the average peel strength. Report the peel strength with an accuracy of 0.001 gf.

[0120] The test results are shown in Table 2.

[0121] Table 2

[0122]

[0123] (III) Tensile relaxation test

[0124] 1. Test purpose: To measure the length relaxation rate of elastic materials after aging.

[0125] 2. Apparatus: Flat cardboard

[0126] 3. Preparation before the test:

[0127] Confirm that the surface of the flat cardboard is smooth and free of damage such as indentations and impurities. Cut a material sample 50 mm wide and 120 mm long.

[0128] 4. Test method:

[0129] Fix one side of the sample to a flat plate with staples as the starting position for stretching (i.e. 0mm). Use a marker to mark the 100mm position (L1) on its surface in the stretching direction of the material, and mark the position to be stretched on the flat plate (such as 250mm, at this time the stretching rate is 150%). Stretch the sample so that the two marked points coincide, and fix the other side of the material to the cardboard with staples. Place the marked sample in an oven at a constant temperature of 40°C for 4 hours to perform actual aging simulation. After 4 hours, take out the sample and remove the second staple, then the sample shrinks. Measure the distance L2 from the red dot on the surface of the material to the starting point at this time, then the length failure rate of the elastic material is:

[0130] (L2-L1) / L14×100%, report the failure rate with an accuracy of 0.01%. The test results are shown in Table 3.

[0131] (IV) Tensile length test

[0132] 1. Test purpose: With the help of the elasticity of the material itself, the material is stretched to increase its length in the CD or MD direction to determine its stretched length.

[0133] 2. Test instrument: tensioner

[0134] 3. Preparation before the test:

[0135] Clean the tensioner so that there is no buildup of debris and no indentations or other damage to the grip surfaces.

[0136] Sample preparation: Single cycle test material, width>150mm, length>200mm

[0137] 4. Test steps:

[0138] Use a clamp to fix one side of the single-cycle test material (the fixed length must be >150mm), and set a distance measurement display tool in the vertical direction to record the initial length. Use a uniform and gentle external force to pull the unfixed side of the material at the same time, so that it gradually moves away from the fixed side in a stable state, and the material is stretched in the length direction.

[0139] Actual stretched length (mm) = stretched length (mm) - original length (mm)

[0140] The test results are shown in Table 3.

[0141] Table 3

[0142]

[0143] (V) Air permeability test

[0144] 1. Test purpose: This test method is used to determine the rate of airflow through a sample of known area. The larger the result, the larger the pores of the material and the stronger the air permeability.

[0145] 2. Test instrument: TEXTEST INSTRUMENT-FX 3300 LabAir air permeability tester (test area 32cm 2 , test pressure 125Pa)

[0146] 3. Preparation before the test:

[0147] Connect the power supply, turn on the air permeability tester, and preheat for at least 5 minutes to allow the pressure sensor to stabilize.

[0148] Sample preparation: Use a paper cutter to cut the sample into a size of 12×12 inches.

[0149] 4. Test method:

[0150] Remove the rubber sheet and press the NULL RESET key to reset the pressure sensor to zero and turn off the red signal light. Set RANGE to "8". Select the appropriate measurement unit, test pressure and test head. Place the sample on the lower test head and clamp it. Press the clamping handle until the vacuum pump starts automatically.

[0151] Use the range knob when the stable range indicator is in the green or yellow area. When the range indicator is red, the test result is wrong; if the range indicator is red at the upper end, select a higher range and turn the range knob to the right; if the range indicator is red at the lower end, select a lower range and turn the range knob to the left.

[0152] After a few seconds, the number displayed on the digital display gradually increases until it stabilizes. At this time, the digital display plus the pre-selected unit is the air permeability of the sample. Press the clamping handle for 1 second, the sample is relaxed, and the vacuum pump is turned off.

[0153] Record the reading on the digital display, the unit of measurement (ft 3 / ft 2 / min), test pressure and test head dimensions.

[0154] The test results are as follows:

[0155]

[0156] (VI) Raw material basis weight test

[0157] 1. Test purpose: To convert the unit weight of the material based on weight and area.

[0158] 2. Test instrument: balance

[0159] 3. Sample preparation:

[0160] Remove the rest of the abnormal area from the test material. Choose a sample with an area of ​​no less than 130 cm² (20 inches²).

[0161] 4. Test steps:

[0162] Taree the balance to zero. Place the sample on the balance or weighing pan so no part of the sample protrudes over the edge of the balance. Record the weight of the sample.

[0163] Calculate the area of ​​the sample using the formula: square inches = length x width.

[0164] To calculate basis weight, the formula is: basis weight = weight (g) / area.

[0165] The test results are as follows:

[0166]

[0167] The above test results show that:

[0168] 1. Tensile strength and elongation:

[0169] 1) Material width direction: The tensile strength of the embodiment of the present invention is slightly lower than that of the Kimberly-Clark elastic film and the ordinary rubber band, which is acceptable considering the reduced basis weight of the wrapped non-woven fabric. The elongation is at the same level.

[0170] 2) Material length direction: The tensile strength of the embodiment of the present invention is at the same level as that of the Kimberly-Clark elastic film and ordinary rubber bands, and the elongation is significantly improved.

[0171] 2. Peel strength: The embodiment of the present invention is at the same level as ordinary rubber bands and is significantly better than Kimberly-Clark elastic film.

[0172] 3. Tensile relaxation rate: The embodiment of the present invention is at the same level as the Kimberly-Clark elastic film.

[0173] 4. Stretch length: The embodiment of the present invention is at the same level as the Kimberly-Clark elastic film.

[0174] 5. Air permeability: The air permeability of the embodiment of the present invention is weaker than that of ordinary rubber bands, but better than that of Kimberly-Clark elastic film.

[0175] 6. Raw material basis weight: The overall basis weight of the embodiment of the present invention is comparable to that of ordinary rubber bands and significantly lower than that of elastic films, which helps to improve air permeability and optimize costs. Comparative Example 1 is also significantly lower than Kimberly Clark's conventional elastic film.

[0176] Definition of terms

[0177] In the present invention, the term "nonwoven fabric" or "nonwoven web" generally refers to a web having a structure of individual fibers or yarns, but not necessarily in a discernible manner such as a knitted fabric. Examples of suitable nonwoven or nonwoven fabric webs include, but are not limited to, meltblown webs, spunbond webs, bonded-carded webs, airlaid webs, coformed webs, hydroentangled webs, and the like.

[0178] In the present invention, the term "elastomeric" or "elastic" generally refers to a material that is stretched in at least one direction (e.g., MD direction) by application of a stretching force, and that contracts / recovers to approximately its original dimensions by release of the stretching force. For example, a stretched material may have a stretched length that is at least about 50% longer than its relaxed, unstretched length, and, by release of the stretching force, may recover to a length within at least 50% of its stretched length. A hypothetical example may be a 1 inch long sample of material that may be stretched to at least 1.50 inches and, by release of the stretching force, will recover to a length of no more than 1.25 inches. Ideally, the material contracts or recovers by at least 50%, and even more ideally, at least 80% of the stretched length.

[0179] As used herein, the term "elastic yarn" includes an elastic elongated material, such as but not limited to elastic rubber bands. The elastic rubber bands can be made of spandex in a warp beam manner according to a spinning process.

[0180] "Pant product" (or "pants", "pull-up pants", "training pants", "pre-closed diapers", "diaper pants", "pant diapers", and "pull-on diapers") refers herein to disposable absorbent articles designed for infants or adult wearers with continuous peripheral waist seams and continuous peripheral leg openings. Pants can be constructed with a continuous or closed waist opening and at least one continuous closed leg opening before the article is put on the wearer. Pants can be preformed or pre-fastened using various techniques, including but not limited to joining the parts of the article together using any refastenable closure member and / or permanent closure member (e.g., seams, heat bonds, pressure welds, adhesives, cohesive bonds, etc.). Pants need to be preformed anywhere along the circumference of the article in the waist region (e.g., side fastened or seamed, front waist fastened or seamed, rear waist fastened or seamed).

Claims

1. An elastic composite material, comprising: First nonwoven fabric; The second nonwoven fabric, and A plurality of adhesive elastic bands are disposed between the first nonwoven fabric and the second nonwoven fabric, wherein the adhesive elastic bands are SEBS copolymers or contain SEBS copolymers, The first nonwoven fabric and the second nonwoven fabric are bonded by the plurality of adhesive elastic bands to form the elastic composite material, and the adhesive elastic bands impart elasticity to the elastic composite material.

2. The elastic composite material according to claim 1, wherein: The elastic composite material has a longitudinal dimension and a transverse dimension, the adhesive elastic band comprises a plurality of adhesive elastic bands oriented in the longitudinal direction, and the plurality of adhesive elastic bands oriented in the longitudinal direction are spaced apart from each other in the transverse direction; and / or The adhesive elastic tape includes a plurality of adhesive elastic tapes oriented in a transverse direction, and the plurality of adhesive elastic tapes oriented in the transverse direction are spaced apart from each other in a longitudinal direction.

3. The elastic composite material according to claim 1, wherein: The adhesive elastic layer is entirely composed of SEBS copolymer.

4. The elastic composite material according to claim 1, wherein: The SEBS copolymer has a value of, but is not limited to, 0.88-0.96 g / cm 3 The density is preferably 0.96 g / cm 3 ; Preferably, the weight average molecular weight of the SEBS copolymer is 100,000 to 200,000, more preferably 130,000 to 150,000; Preferably, the adhesive elastic band comprises a mixture of SEBS having a weight average molecular weight of 140,000 to 145,000 and SEBS having a weight average molecular weight of, including but not limited to, 130,000 to 135,000, in a weight ratio of 3.5 to 5.5: 1; Preferably, the content of styrene monomer in the SEBS copolymer is 13-58 wt%, preferably 18-31 wt%; Preferably, the SEBS copolymer has a melt flow rate (MFR) of 1-18 g / 10 min, preferably 7-18 g / 10 min, measured at 230° C. and a load of 2.16 kg.

5. The elastic composite material according to any one of claims 1 to 4, wherein The total basis weight of the plurality of adhesive elastic tapes is 60 g / m 2 Or lower, preferably 48-50g / m 2 ; Preferably, the width of the adhesive elastic band is 5 to 50 μm, more preferably 10 to 30 μm.

6. A method for preparing the elastic composite material according to any one of claims 1 to 5, comprising: stretching a plurality of bonded elastic filaments in a machine direction; placing the plurality of adhesive elastic threads between the first nonwoven fabric and the second nonwoven fabric along a machine direction in a stretched state; The first nonwoven fabric and the second nonwoven fabric are bonded by the plurality of bonding elastic threads by means of heat bonding, pressure bonding and / or ultrasonic bonding, and a plurality of bonding elastic bands are formed between the first nonwoven fabric and the second nonwoven fabric, and the elastic composite material is obtained after relaxation, The adhesive elastic filaments comprise SEBS copolymers, and the adhesive elastic filaments impart elasticity to the elastic composite material.

7. A method for preparing an elastic composite material, comprising heating an adhesive elastic material comprising a SEBS copolymer to 130-190° C. to melt the adhesive elastic material, using a spinneret assembly to form an adhesive elastic thread from the melted adhesive elastic material, placing the adhesive elastic thread between a first non-woven fabric and a second non-woven fabric in a stretched state, bonding the first non-woven fabric and the second non-woven fabric by thermal bonding, pressure bonding, self-bonding of the material itself, or ultrasonic bonding, and forming a plurality of adhesive elastic bands between the first non-woven fabric and the second non-woven fabric, in, The adhesive elastic band is SEBS or SBC copolymer or contains SEBS copolymer, wherein the adhesive elastic band between the first non-woven fabric and the second non-woven fabric can be plain and patternless or can form a specific pattern, including but not limited to corrugations, S curves, and channels.

8. The preparation method according to claim 6 or 7, wherein: The heating temperature is 130-190°C, preferably 170-190°C; Preferably, the diameter of the adhesive elastic thread is 2-20 μm, more preferably 5-16 μm. Preferably, the first nonwoven fabric and / or the second nonwoven fabric is an elastic nonwoven fabric; Preferably, the preparation method further comprises: stretching the elastic composite material along a machine direction to adjust the tension of the elastic composite material.

9. The preparation method according to claim 6 or 7, wherein: The preparation method further comprises the following steps of preparing the bonded elastic thread: heating an adhesive elastic material comprising a SEBS copolymer until it melts; The melted adhesive elastic material is formed into adhesive elastic yarns by using a spinneret assembly.

10. The preparation method according to claim 6 or 7, wherein: The arrangement and spacing of the adhesive elastic bands are as follows: the adhesive elastic bands are elastically oriented in the longitudinal direction and are spaced apart from each other in the transverse direction, and the spacing between the elastic threads is 1-8 mm, preferably 1.5-4 mm.

11. A pant product having a front region, a back region, and a crotch region extending between and connecting the front region and the back region, the absorbent article comprising: an absorbent assembly extending longitudinally between said front region and said back region and comprising an inner layer facing toward the wearer, an outer layer facing away from said wearer, and an absorbent structure disposed between said inner layer and said outer layer; as well as a waist component attached to the absorbent component and defining a waist opening of the absorbent article, It is characterized in that the waist component comprises the elastic composite material according to any one of claims 1 to 5, or is formed by the elastic composite material according to any one of claims 6 to 10.

12. The pant product of claim 11, wherein the elastic zones of the waist feature are as follows: The front waist of the trousers product is divided into four elastic regions from top to bottom along the longitudinal direction, and the width ratio and stretch ratio of each elastic region are as follows: the width ratio of the first region is 5%-8%, and the stretch ratio is 270%-310%; the width ratio of the second region is 10%-20%, and the stretch ratio is 220%-270%; the width ratio of the third region is 5-15%, and the stretch ratio is 180%-250%; the fourth region includes but is not limited to an inelastic region or a region with lower elasticity than the third region; The rear waistline of the pants product is divided into four elastic zones from top to bottom along the longitudinal direction, and the width ratio and stretch ratio of each elastic zone are as follows: the width ratio of the first zone is 5%-8%, and the stretch ratio is 270%-310%; the width ratio of the second zone is 10%-20%, and the stretch ratio is 220%-270%; the width ratio of the third zone is 15%-35%, and the stretch ratio is 180%-250%; the fourth zone includes but is not limited to an inelastic zone or an elasticity lower than that of the third zone.

13. Use of the elastic composite material according to any one of claims 1 to 5 in absorbent articles such as diapers, training pants, absorbent underpants, night pants, and day pants.

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